Auto shutdown android mobile when battery is 20%

I have heard that it is good for battery to charge battery is 20%. Is there is any good app, tool, settings or something like that to auto shutdown android mobile when battery is 20%.

How to force shutdown when in a bootloop?

Got into a bootloop on Exodus, and now it just spins at the X splash screen. I tried the hard shut down, but it acts as a reboot. I cannot get this thing to turn off to save my battery. I can't mess with it until tonight. Any help? Never had this problem on any phone I've rommed. Booting into recovery and shutting down is an option, but my question is why does it keep restarting if I was just using the power button?

Shutdown sound/animation does not work

Hello
I have tried asking this question in other places but no luck :(
Basically i got a android (Samsung s3) and now i am customizing it for myself.
And now i am stuck. I decided to change startup and shutdown animations and sounds just because. For startup i successfully changed it to the droid peeing on the apple logo (because it is funny) but for the shutdown i want just a sound file (a turret from portal saying shutting down). I followed the thread "HOW TO: Change bootup/shutdown animations and sounds" but i cannot get it to work. I have tried various formats and many ways of naming the file i have found on google but no success. Only thing that i noticed is that i did not have a shutdown file before i started messing with it. Afterwards i tried importing a shutdown animation from "forum.xda-developers . com/lg-g3/themes-apps/bootanimation-android-5-0-l-boot-t2814467" and that does not even show the animation.
Thanks